Interfacing of the Safety PLC to the Robot Controller

  • Hello everyone.

    This is my first post on this forum, so please forgive me if I cross any rules and regulations of this forum.


    I have a Pilz safety PLC which I am using to send certain signals to the robot controller to stop when the fence gate is OPEN. This is my first time doing it. After reading the manual I understand that we have to send signals to EAS1-EAS11 and EAS2-EAS21 for the safety fence.


    Could anyone please explain how can i connect my SAFETY PLC to the robot controller? Does it have to be through Ethernet/IP or should I hardwire it?

  • Depends entirely on what brand of robot you are using, and what options that robot has. As far as I'm aware, on any robot, the hardwired safeties and the network safeties are mutually exclusive. That is, if the robot was purchased with the Ethernet/IP safety option, then the hardwired safeties are no longer usable (and may in fact be physically removed).

  • Welcome to the forum! As SkyeFire already said, we need to know which robot brand (controller type and software version would also be helpful) you are using. Based on the designation of the fence terminals I suspect it is a FANUC. Is your safety PLC a PNOZmulti 2? Am I right with my assumptions?


    If yes, the PNOZmulti 2 is not supporting CIP Safety. That means, for the safety signals (such as external emergency stop or fence) you need to use hardwired signals.

  • Hello Everyone,

    The robot is a Fanuc Arcmate120iD.

    The PLC that we are considering purchasing is Pilz PSSu PLC1 FS SN SD with Output and Input cards PSSU E F 2DOR 8 and PSSU E F 4 DI.


    The signals EAS1-EAS11 and EAS2 - EAS21 have jumpers in them at the moment. We are also using Ethernet/IP but that is to control certain parameters like the ENable and other signals from an HMI and also to run certain programs. The ethernet connection is done with a different PLC.


    So should I control the robot controller signals through Ethernet/IP?

    Or should I like hardwire a relay to the output module of the safety PLC and then that relay will further be connected to the robot controller signals?

  • We are also using Ethernet/IP but that is to control certain parameters like the ENable and other signals from an HMI and also to run certain programs. The ethernet connection is done with a different PLC.

    Some things are not yet clear to me at the moment. What brand is this "different PLC"? Is it a also a safety PLC?


    Is your robot connected to the other PLC via EtherNet/IP? Is the robot already controlled by the other PLC?

    The PLC that we are considering purchasing is Pilz PSSu PLC1 FS SN SD with Output and Input cards PSSU E F 2DOR 8 and PSSU E F 4 DI.

    As far as I know the Pilz PSSu only supports SafetyNET p for safety-related communication.

    So should I control the robot controller signals through Ethernet/IP?

    Or should I like hardwire a relay to the output module of the safety PLC and then that relay will further be connected to the robot controller signals?

    Are you still talking about the safety signals?! If yes, the Pilz PSSu is also not supporting CIP Safety which would be required for safety-rated communication when using EtherNet/IP. That means, you need to use hardwired signals. See also my other post.


  • Hello everyone,

    Thank you for your responses.

    Let me answer some questions first:


    1. DS186 The second plc is a normal plc, not a safety plc. It is from PANASONIC The model number for the same is FP0H C32ET.

    2. Yes the robot is connected to the above plc via Ethernet/IP. Using this connection we run the welding programs directly from an HMI screen rather than running it from the teach pendant of the robotic arm.

    3. Yes I am still talking about safety signals. Thank you for mentioning that the PSSu series does not support the CIP Safety.


    So if I am going to hardwire it, the best choice that I think to wire the output of the safety plc to the robot controller is through a relay, as in to protect the safety plc from any kind of short circuit.

    Please correct me if i am wrong.

    Thank you

  • The PLC that we are considering purchasing is Pilz PSSu PLC1 FS SN SD with Output and Input cards PSSU E F 2DOR 8 and PSSU E F 4 DI.

    So if I am going to hardwire it, the best choice that I think to wire the output of the safety plc to the robot controller is through a relay, as in to protect the safety plc from any kind of short circuit.

    The PSSu E F 2DOR 8 is a relay module with potential-free outputs. Therefore, you can directly connect the outputs of the module to the EAS terminals of the robot controller.

  • Amazing

    So since they are relay module potential-free outputs , i wouldn't require any extra relay or a contactor to connect them to the PLC ?

    Also could anyone please tell me how EAS and EES inputs work under the robot controller? Like will I have to code them in the robot controller end or in the safety plc end?


    Or just the direct connection and the robot controller will automatically monitor these inputs?

  • So since they are relay module potential-free outputs , i wouldn't require any extra relay or a contactor to connect them to the PLC ?

    Option1: Connect the fence outputs to the Pilz input module and the Pilz output module to the EAS terminals of the robot controller. Of course, this requires some logic in your safety PLC.

    Or just the direct connection and the robot controller will automatically monitor these inputs?

    Option 2: Connect the fence directly to the EAS terminals of the robot controller. If the outputs of your safety device (for the fence) are potential-free it is no problem. If the safety device is using OSSDs you probably need relays inbetween.

    Also could anyone please tell me how EAS and EES inputs work under the robot controller? Like will I have to code them in the robot controller end or in the safety plc end?

    You just have to connect EAS and EES. After that, you need to test and verify the proper function of the safety functions.

  • Hi all,


    Sorry for jacking the post, however I have similar questions. Hoping someone can help or point me in the right direction.


    Robot Controller: r30ib plus

    Safety Option: EtherNet/IP

    PLC: Compact Guardlogix

    Intent: Use CIP safety for communication of safety signals

    Problem: Cannot get communication of the robot safety signals to the PLC

    Actions: The robot has been owned by PLC with matching signature a few times. . .module is not faulted @PLC and the ADP indicates running status with successful pings at robot controller. The PLC still does not recognize input from the robot controller.

    Background: Robot was initially integrated with fence hardwired to safety input Controller, those terminations may still be in place.


    What are the thoughts as to what may have the signals failing to reach PLC? DS186, HawkME


    Thanks in advance,

    BashBot

    Edited once, last by BashBot ().

  • Are you seeing safety level comms happening when you look under Etherenet/IP, then safety? Have the SafeIO definitions been updated in the DCS page?

    Yes, there are valid txns and counts.

    How do you mean updated? However, I think so. Yes.


    Is it normal for the IO_UOP_CFG to be 0,-1,-1,-1,-1,-1,-1

  • Sounds like the SafeIO definitions have not been assigned. Out of the box, nothing is setup in the safety side on the robot. You need to assign safety level inputs and outputs for stuff like fence open, estop, robot estop pressed, deadman pulled in, etc.


    Here is an example. CSIs are safety inputs from the PLC, CSOs are safety outputs from the robot.

    The Dual Check Safety manual explains everything in detail.


    Check out the Fanuc position converter I wrote here! Now open source!

    Check out my example Fanuc Ethernet/IP Explicit Messaging program here!

  • Thank you, major oversight on my part which was discovered before I got back to this thread. But yes! Exactly what was missing. *facepalm

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